At first, she adhered to a very strict diet. She became a vegan for a while and cut out all dairy produce. She also added 'super-foods' to her diet and ate almost entirely organic.

Vicky said: "Fresh fruit, vegetables and juices are great, and frozen berries are fantastic as a superfood.

"Turmeric kind of makes cancer cells commit suicide and ginger and garlic are great to cook with."

She prepares all her food from scratch, makes her own body lotions from natural ingredients and only uses chemical-free cleaners and detergents.

"I decided that I was going to help myself and do as much as I could," she said.

Another element of her lifestyle is moderate exercise, which she believes was helpful in her recovery from cancer.

Vicky made her decision based on the side effects she could expect from Tamoxifen.

"It was the worry of the drugs and the side effects, I didn't want to have to worry about it, I wanted to be free," she said.

The national research study is looking at how lifestyle can help prevent the recurrence of breast cancer after surgery. It is the largest of its kind in the world, involving 56 hospitals around the UK and 3,400 patients who have had the disease.

For the past four years, Vicky has provided blood and urine samples and filled in regular questionnaires about her well-being, diet and lifestyle as part of the national research.

She has another year left of the trial and some findings are expected later this year and the full results will be published next year.

Vicky is hoping to mark her five-year remission in August 2013 and is getting ready to marry her fiance Michael in September.

She added: "People can die, or come back from it and enjoy life, you've just got to be thankful you're still around. Make the most of life, everything will always be alright in the end."

Dr Steve Kelly, an oncologist specialising in treating patients with breast cancer, based at Derriford Hospital, said: "Breast cancer deaths have been going down steadily for over 20 years thanks to surgery, chemotherapy and radiotherapy - all have helped.

"But there are three things patients can do to help themselves, it doesn't guarantee survival, but it does help.

"The first is to exercise for thirty minutes three days a week, the second is to not gain any weight and the third is to reduce fat intake.

"These things help to reduce the chance of cancer coming back. For this patient, four years on now, it is still early days."

Vicky's father Dr John Sewart, aged 85, from Saltash, said: "I gave her advice when she asked for it.

"I was answering as a father first and a doctor second. It wasn't difficult, I agreed with what she was planning to do, and I agreed with her decisions."